Task Factories

A task factory is represented by the System.Threading.Tasks.TaskFactory class, which creates Task objects, or the System.Threading.Tasks.TaskFactory<TResult> class, which creates Task<TResult> objects. Both classes contain methods that you can use to:

• Create tasks and start them immediately. For more information, see Task Parallelism (Task Parallel Library).

• Create task continuations that start when any or all of an array of tasks complete. For more information, see Continuation Tasks.

• Create tasks that represent pairs of begin/end methods that follow the Asynchronous Programming Model. For more information, see TPL and Traditional .NET Framework Asynchronous Programming.

The Task class has a static property that represents the default TaskFactory. Typically, TaskFactory methods are invoked by using the Factory property, as shown in the following example.

[Visual Basic]

Dim taskA as Task = Task.Factory.StartNew(Sub( ...))

[C#]

Task taskA = Task.Factory.StartNew( () => ...);

In most scenarios, you do not have to derive a new class from TaskFactory. However, it is sometimes useful to configure a new TaskFactory and then use it to specify certain options or to associate tasks with a custom scheduler. The following example shows how to configure a new TaskFactory that creates tasks that all use the specified TaskScheduler and have the specified TaskCreationOptions options.

class Program
{
   static CancellationTokenSource cts = new CancellationTokenSource();

   static TaskFactory _factory = new TaskFactory(
      cts.Token,
      TaskCreationOptions.PreferFairness,
      TaskContinuationOptions.ExecuteSynchronously,
      new MyScheduler());

   static void Main(string[] args)
   {
      var t2 = _factory.StartNew(() => DoWork());
   }

   static void DoWork() {/*...*/ }
}